An Edge-On Close Encounter with Jupiter   
       
   Feb 6, 2015: Every 13 months, Earth and Jupiter have a close encounter.   
   Astronomers call it an "opposition" because Jupiter is opposite the Sun in the   
   sky. Our solar system's largest gas planet rises in the east at sunset, and   
   soars overhead at midnight, shining brighter than any star in the night sky.   
       
   This year's opposition of Jupiter occurs on Feb. 6th.  It isn't an ordinary   
   close encounter with Earth (approximately 640 million kilometers), but in Feb.   
   2015, Jupiter is edge on to the Sun.   
       
   http://science.nasa.gov/media/medialibrary/2015/02/04/4shadows.jpg   
       
   Efrain Morales Rivera of Aquadilla, Puerto Rico, photographed multiple shadows   
   transiting the face of Jupiter on Jan. 24th. A full-sized version of his image   
   matches each shadow to a moon.   
       
   In a rare coincidence, Jupiter's opposition on Feb. 6th coincides almost   
   perfectly with its equinox on Feb. 5th when the Sun crosses Jupiter's   
   equatorial plane. It is an edge-on apparition of the giant planet that sets   
   the stage for a remarkable series of events.  For the next couple of months,   
   backyard sky watchers can see the moons of Jupiter executing a complex series   
   of mutual eclipses and transits.   
       
   The eclipses have already started.  On Jan. 24th, for example, three of   
   Jupiter's moon's, Io, Europa, and Callisto, cast their inky-black shadows on   
   Jupiter's swirling cloudtops.  The "triple shadow transit" happened while   
   Jupiter was high in the sky over North America, and many backyard astronomers   
   watched the event.   
       
   )As Earth's crosses the plane of Jupiter's equator in the weeks and months   
   ahead, there will be many mutual events.  For instance, on Feb. 5th, volcanic   
   Io will cast its shadow on Mercury-sized Ganymede, Jupiter's largest moon.  On   
   Feb. 7th, icy Europa, home to what may be the solar system's largest   
   underground ocean, will cast its shadow on IEvents like these will continue,   
   off and on, until July 2015.   
       
   During the last edge-on apparition in 2009, some observers managed to obtain   
   the first resolved time-lapse videos of mutual phenomena. Experienced amateur   
   astronomers recorded satellites ducking in and out of one another's shadows,   
   moons in partial and total eclipse, and multiple shadows playing across the   
   face of Jupiter.  Backyard telescopes have come a long way in the past 6   
   years, so even better movies can be expected this time.   
       
   You don't have to be an experienced astronomer to experience Jupiter's   
   opposition.  Anyone can see the bright planet rising in the east at sunset. It   
   outshines by far anything else in its patch of sky.  Point a small telescope   
   at the bright light and, voila!--there are Jupiter's cloud belts and storms,   
   and the pinprick lights of the Galilean satellites circling the gas giant   
   below.   
       
   Try it.  640 million kilometers won't seem so far away at all.   
       
   Credits:   
       
   Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:   
   Science@NASA   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)